Armchairs used currently in public transport vehicles, such as coaches, trains, buses or airplanes, comprise a seat in which the armchair user is seated alongside a backrest. To increase the user's comfort, the backrest may be articulated to the seat, thanks to which it can be reclined or be in a substantially vertical position.
This type of armchairs usually also comprise armrests that can be folded from a substantially horizontal position to a substantially vertical position.
Armrests are usually articulated in the back part of the seat so that when the armrest is placed in its vertical position parting from the horizontal position, the armrest in a vertical position by the backrest. This position leaves practically the whole of the armrest protruding from the front part of the set.
This type of armrests are inconvenient because they are a bother when in a vertical position, as they take up space, an aspect that is extremely important given that the armchairs used in public transport vehicles are only allowed a maximum width.
This inconvenience is increased when two armchairs are placed side by side with armrests between both armchairs. Given that they take up space when in a vertical position, armchairs are usually equipped with a single armrest measuring the normal width of a regular armrest, which implies an inconvenience for the users of both armchairs.